1. Field of the Invention
The invention generally relates to monitoring fluid movement in a formation.
2. Description of the Related Art
The following descriptions and examples are not admitted to be prior art by virtue of their inclusion in this section.
For purposes of producing a hydrocarbon-based fluid (oil or gas) from a formation, a wellbore typically is drilled into the formation and a well completion is then installed in the wellbore. The well completion generally includes a production tubing string that extends into the wellbore for purposes of communicating the produced well fluid to the surface. The production tubing string may include various downhole tools to control the production of the hydrocarbon-based fluid.
To allow better control over the production, the well may be segmented into isolated production zones so that the production in each zone may be independently controlled. For purposes of establishing isolated production zones, a typical production tubing string may include devices called packers, which form annular seals between the string and the wellbore wall or casing (if the wellbore is cased). The production tubing string may further include valves that control the inflow of well fluid from the various production zones.
A conventional well may also contain a downhole telemetry system for such purposes as remotely monitoring downhole conditions (pressures and temperatures, for example) and controlling the tools of the production tubing string from the surface of the well. The downhole telemetry system may employ wired or wireless communication. Wired communication may involve communicating over, for example, a wireline cable or over an electrical line that is installed in a tubing string. Wireless telemetry may involve numerous different forms of communication, such as fluid pressure communication, acoustic communication, electromagnetic (EM) communication, etc.
Over the lifetime of a well, the composition of the well fluid that is produced in a given production zone may vary. For example, a given production zone may initially produce a relatively high percentage of hydrocarbon-based fluid. However, over the lifetime of the well, an increasing percentage of water may enter the zone, thereby eventually resulting in an undesirable degree of water production. When this occurs, conventionally, the flow through the valve that controls production from the affected zone is appropriately restricted or shut off to reduce the degree of produced water.